As a device which converts direct-current power into alternating-current power, there is a device using a magnetic energy recovery switch (refer to Patent Literature 1). The magnetic energy recovery switch mentioned in Patent Literature 1 has four switches and a capacitor. The four switches are connected so as to constitute a full-bridge circuit. The capacitor is connected between direct-current terminals of the full-bridge circuit. A load is connected between output terminals of the full-bridge circuit. The four switches each have a positive electrode terminal and a negative electrode terminal. A conduction state from the negative electrode terminal to the positive electrode terminal of the four switches is a state in which a current constantly flows. On the other hand, in a conduction state from the positive electrode terminal to the negative electrode terminal of the four switches, a state in which a current flows and a state in which a current does not flow are switched by a signal from the exterior. Such a magnetic energy recovery switch circuit allows a frequency of the alternating-current power converted from the direct-current power to be changed by changing a frequency at which on and off of the four switches are switched.
Further, Patent Literature 2 mentions that a capacitor improving a power factor on an input side of a magnetic energy recovery switch is provided on the input side of the magnetic energy recovery switch. Further, Patent Literature 2 mentions that a transformer is connected to both ends of a capacitor of the magnetic energy recovery switch and a capacitor is connected in series with the transformer and the capacitor of the magnetic energy recovery switch. This capacitor is the one for making an input voltage to the transformer large.
Further, Patent Literature 3 discloses that a DCDC converting device is constituted by using two magnetic energy recovery switches.
Further, Patent Literature 4 mentions that a capacitor is connected in parallel with an inductive load between alternating-current terminals of a magnetic energy recovery switch. Patent Literature 4 indicates that connecting the capacitor in parallel with the inductive load makes it possible to reduce a current flowing through the magnetic energy recovery switch.